Engineering principles for the design of a new / existing mine’s personnel transportation system (Case study Bafokeng Rasimone Platinum Mine)

Abstract:

This document describes the re-engineering principles applied in the design of a personnel transportation system for a platinum mine in the Rustenburg area of South Africa. It incorporates conveyor belt travelling, chairlift operation and also includes consideration of proposed changes / modifications to existing conveyor belt infrastructure.
The purpose of the project was to identify the appropriate option and / or combination of transportation options through a process of evaluation that would be safe in terms of personnel transportation and cost effectiveness. If alternative measures could be found to transport personnel (in other words not using belt riding as a means of transport), it would have a significant positive spin-off increasing the availability of the belt, to increase production. This document therefore explores the feasibility of new interventions investigated.
The design in consideration at the Bafokeng Rasimone Platinum Mine consisted of two shaft systems, namely the North Shaft and South Shaft. Each shaft system comprises of twin decline shafts. One of which is equipped with a conveyor belt for rock and personnel transportation and the other with a winder for track bound material transport. From the date of commissioning of the shafts, the conveyor belt was used for personnel transportation. The conveyor belt is equipped with platforms for getting off and on the belt and a number of safety devices designed to ensure the safety of personnel travelling on the conveyor belt. Intensive training in the practical aspects of belt riding was given to each and every person and unsupervised riding on the belt was only undertaken once belt riding competence was demonstrated. Despite this, the safety results were poor, having experienced 106 injuries between 2006 and May 2013. No fatalities were reported during this period.
It was therefore needed to investigate alternative means for personnel transportation or through engineered solutions to the current conveyor belt infrastructure in the safest, most effective and most economical way. There was a major risk of safety related stoppages being imposed following another belt accident / incident. This would prevent the mine from transporting personnel underground by belt and subsequently result in major production losses. From the commissioning of the Phase 2 shaft deepening project on both shafts, the decision was to install dedicated chairlifts for personnel transportation opposed to the man riding conveyor belt installed in the Phase 1 area.
The chairlift installations were in operation since 2004 and no chairlift related incidents were recorded thus far. According to safety statistics it was clear that the chairlift installation is the safer method for the transportation of people in the shaft.
To fulfil the objectives / scope of this investigation / study, it was recommended that both primary (new chairlift decline with infrastructure) and secondary options (modifications to the current conveyor belt infrastructure) be considered for implementation on both North Shaft and South Shaft to reduce / eliminate accidents / incidents as a result of belt transportation. The associated CAPEX would be approximately ZAR 200 million. Considering the future impact on the business as a whole, this would definitely be CAPEX well spent!